Learn Portuguese (Portugal): O voo de Lisboa foi rápido.

In this sentence, foi is the past tense of ser (to be), meaning "was". The verbs ser and ir share the exact same forms in the simple past! You always have to use context to tell them apart. Because it's followed by the adjective rápido, it makes sense that it means "was fast" rather than "went fast".

Why do we use de Lisboa instead of da Lisboa?

In Portuguese, most cities (like Lisbon) don't take a feminine or masculine "the" before them. Because there is no article to combine with, the preposition de (from) stays exactly as it is, rather than combining into da (de + a).

How do you pronounce a word with a double 'o' like voo?

You don't pronounce two separate vowel sounds. In European Portuguese, the double 'o' in words like voo (flight) blends into a single, slightly drawn-out "oh" sound. Fun fact: you might see this spelled as vôo in older texts, but the accent mark was removed in a spelling reform.

Would rápido ever change its ending?